In a rare, detailed look at sexual assault and harassment on a university campus, M.I.T. revealed Monday that among undergraduates who replied to a survey, at least 17 percent of women and 5 percent of men said they had been sexually assaulted.

That is similar to the findings of a handful of other studies, including a frequently cited survey in which 19 percent of undergraduate women said they had experienced sexual assault, or attempted sexual assault. But there have been few surveys that looked at experiences and attitudes at particular colleges — and victim advocates said they knew of none with the clarity and depth of the M.I.T. survey.

“This is the best one I’ve seen, and I really commend M.I.T. for doing it, and publishing the results,” said Colby Bruno, senior counsel at the Victim Rights Law Center, who has handled many campus cases.

Activists against sexual assault have argued that such campus “climate” surveys are crucial to exposing the extent of the problem, and such surveys were among the steps proposed this year by both a White House task force and a bipartisan group of senators.

“Sure, the data tells us things that we maybe didn’t want to hear,” said Cynthia Barnhart, chancellor of the Massachusetts Institute of Technology. But she said one of the clearest — and most disturbing — conclusions she drew from the results was that “there is confusion among some of our students about what constitutes sexual assault,” indicating a need for more open discussion.

The institute has taken a number of steps to curb sexual assault and improve the way it responds to offenses, though there is no clear way to measure how effective those have been. The number of officially reported assaults has risen this year, which often happens when more attention is devoted to the issue.

M.I.T. asked all of its nearly 11,000 graduate and undergraduate students to take the survey, and about 35 percent did so. Dr. Barnhart cautioned that it was not possible to say how different the results would have been if everyone had taken part.

John D. Foubert, a professor of higher education at Oklahoma State University who studies campus sexual assault, praised the M.I.T. study, noting that “very few schools have publicly released any data.” But he expressed concern that different surveys have not asked the same questions, or have worded them differently, making comparisons harder. He added that a survey of a random sampling of students, with a high response rate, might carry greater weight than M.I.T.’s self-selected sample.

The institute asked about specific types of contact, and how students characterize what happened, illustrating how much perceptions can vary.

M.I.T. asked about several forms of unwanted sexual contact, from touching to penetration, “involving use of force, physical threat or incapacitation,” that it said clearly constituted sexual assault — the kind that 17 percent of undergraduate women and 5 percent of undergraduate men said they had experienced. In addition, 12 percent of women and 6 percent of men said they had experienced the same kinds of unwanted sexual contact, but without force, threat or incapacity — some of which, depending on the circumstances, can also be sexual assault.

Yet when asked if they had been raped or sexually assaulted, only 11 percent of female and 2 percent of male undergraduates said yes.

There was a similar result on sexual harassment. Among undergraduate respondents, large majorities of men and women said they had heard sexist remarks and inappropriate comments about people’s bodies; more than one-third said someone had uttered crude sexual remarks to them directly; nearly as many had been subjected to people’s tales of sexual exploits; and a smaller number had received offensive digital messages. About one woman in six said someone had repeatedly asked her for a date, even after being refused.

But the number who described what had happened to them as sexual harassment was relatively small: 15 percent of undergraduate women, and 4 percent of men. Also, 14 percent of women said they had been stalked, and 8 percent said they had been in a controlling or abusive relationship.

Of those who had experienced unwanted sexual contact, most said they had told a friend, but only 5 percent said they had reported it to any campus official. When asked why, more than half said that they did not think it was serious enough to report and that no harm was intended, and nearly half said they thought they were partly at fault.

Large numbers of undergraduates, male and female, also agreed with statements suggesting that blame for the assault did not always rest exclusively with the aggressor. Two-thirds agreed that “rape and sexual assault can happen unintentionally, especially if alcohol is involved”; one-third said it can happen “because men get carried away”; about one in five said it often happened because the victim was not clear enough about refusing; and a similar number said that a drunk victim was “at least somewhat responsible.”

Such views were less prevalent among graduate students, as was sexual assault itself.

Dr. Foubert said he considered many of those responses a form of “excusing the perpetrator and blaming the victim,” and was very concerned about it.

Andrea Pino, an activist who has helped file federal complaints about sexual assault against dozens of colleges, said she hoped other colleges would follow M.I.T.’s example. She said the institute’s survey covered more ground than any she had seen, and did not muddy matters with vaguely worded questions, as some surveys have done.

Prestigious colleges and universities, jealously guarding their reputations, “have been notorious for not being open about this,” said Ms. Pino, co-founder of the group End Rape on Campus. “A big-name school like M.I.T. being ahead of the curve like this matters.”